Chromosomal deletion in patients with malignant pleural mesothelioma.

Malignant pleural mesothelioma (MPM) is associated with frequent deletions of specific chromosomal regions within 1p, 3p, 6q, 9p, 13q, 15q, and 22q. In this retrospective review of our patients with MPM, the tumor tissue of 40 patients (31 male and 9 female) was evaluated for chromosomal deletions and was karyotyped. Chromosomal deletions in regions 1p, 3p, 6p, 9p, 6q, 9q, 22q were observed in 22 of 40 patients (55%). Of this group of 22 patients, 15 (68%) demonstrated deletions in chromosome 6; 12 (54%) exhibited deletions in chromosome 22q; and 13 (59%) had deletions in chromosome 9p. Asbestos exposure was found in only 13 of the 22 patients (59%) with chromosomal deletions. There was no correlation between asbestos exposure and chromosomal deletion (95% CI -0.38-0.23, P=0.63). Chromosomal deletion did not correlate with age (95% CI -0.45-0.14, P=0.29). The majority of patients with chromosomal deletions had epithelial histology (17 of 22 patients; 77%), which was not statistically significant (95% CI -0.14-0.46, P=0.27). Chromosomal deletion is common in tumor tissue of MPM and the inactivation of tumor suppressor genes (TSGs) residing in these chromosomes may contribute to mesothelial cell tumorigenesis.